tmf: Bug 422341: Mouse wheel on horizontal scroll bar a bit too small

- Remove the built-in horizontal scroll bar from the time graph control

- Add method to programatically scroll left or right in time graph
control

- Scroll horizontally instead of zooming on mouse scroll over horizontal
scroll bar, zoom on Ctrl+mouse scroll (Windows)

- Add a horizontal slider to the time graph viewer

- Scroll horizontally and ignore the slider's internal selection event
on mouse scroll, zoom on Ctrl+mouse scroll (Linux)

Change-Id: I5db4cc25306d5bb62efe6790d2dd516ded28a020
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/36522
Tested-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>